Carbon clean walnut shell size

Hi guys about to attempt a carbon clean. What size walnut shells is used?

Thanks in advance

I used Medium on my S5, worked pretty good. I’ll use the same on the RS5 in a few years. NIce thing is, the Intake port cleaning adpater fits 2.0t, 3.0t, 4.0, & 4.2 engines.

I used medium as well when I completed mine not too long ago. It definitely got the job done.